The first steel beams which will eventually bear 6,000 square metres of glass were erected over the Great Court in the middle of the British Museum. Most of the six million visitors who pour into the museum every year have been unaware of the amazing space - the size of a football pitch - which lay hidden at its heart.
The two-acre enclosed courtyard has been unseen by the general public for 150 years since the completion of the famous Reading Room, which lies within it, in 1857.
But the removal of the Reading Room's books to the British Library's new home on Euston Road finally created the possibility of reclaiming the space as the hub of the museum.
The pounds 97.9m transformation at ground level (and below) is being spanned by the spectacular glass and steel roof which will weigh 800 tonnes when it is completed next January.
More than 3,300 individual panes of glass, each a unique triangle, are being made to be slotted into place in a steel web to an overall design by the architect Sir Norman Foster.
A special computer programme was devised by the engineers Buro Happold to work out how to span the space from the museum walls to the edge of the Reading Room cupola - inconveniently placed off-centre - without placing any weight on the Grade I listed building itself. In this, they were helped by the fact that the Victorians never finished the outer wall of the Reading Room properly because it was not visible.
Frances Dunkels, the museum's development spokeswoman, said the area had been a dead space for decades but its restoration to life would ease the flow of visitors through the busy museum.
The new development will include an education centre and galleries allowing the return of the ethnography collections from the Museum of Mankind in Burlington Gardens where they have been since 1970 for lack of space.
The Reading Room itself will be transformed into a library specialising in books on the civilisations and societies represented in the museum. Where it was previously accessible only to those with a reader's ticket, when the work is finished in November 2000, anyone will be allowed in. And in one of the more dramatic changes of all, the Great Court will stay open into the evening as a self-contained cultural complex where visitors can dine at the terrace restaurant or listen to a concert.
Lottery money from the Millennium Commission and the Heritage Lottery Fund is paying for around half of the current project.Reuse content